Answer:
Uniformitarianism can be defined as:
A. illustrated by scientists seeing pillow lava forming only underwater, then theorizing that pillow lava found high in the mountains today did nevertheless form underwater.
Explanation:
So, here a term has been given which is Uniformitarianism which is a term from geology that means a theory which is related to changes of the earth's crust which have occured during the geological history resulted because of the uniform and continuos processes.
It is also known as Doctrine of uniformity. Also can be assumed as that same natural processes and laws that works in our present day observations of scientific methods have always been operated in the universe in past times and are always applicable.
Some examples of uniformitarianism are as follows:
So, here the correct option is A.